On marine containers, an industrial plug serves as a common power receiving interface in a transportation process of the containers. General requirements and dimensional interchangeability requirements of the industrial plug need to meet a standard IEC60309. As shown in FIG. 1, different colors are used for displaying different rated voltages of products in the standard IEC60309. For example, a plug or a socket with a rated voltage of 380-480V AC is red. In addition, as specified in the international standard IEC60309, an industrial red plug or socket which has a rated voltage of 380V AC, 50Hz and 3P+E (3P+earthed) and has an earthing contact in a 3 h position (a 3 o'clock direction, referring to a front view of the plug for a clock position) is only used for a power receiving interface apparatus of an ISO standardized refrigerated vessel (that is, a refrigerated container). However, an industrial plug or socket product which has a rated voltage of 380-415V AC, a 50/60 Hz and 3P+E (3P +earthed) and has an earthing contact in a 6 h position (a 6 o'clock direction) is internationally applied widest and most universally.
In an international logistics transportation industry, many containers need to be under live work in the transportation process to control temperatures in the containers. Now an actual condition is that: when the containers are positioned in a place A, a power transmission interface of an industrial red socket which has a rated voltage of 380V AC, 50 Hz and 3P+E (3P+earthed) and has an earthing contact in a 3 h position (a 3 o'clock direction) is arranged in the place A, but when the containers are positioned in a place B, such a power transmission interface is not arranged in the place B, and only a power transmission interface of an industrial red socket which has a rated voltage of 380-415V AC, 50/60 Hz and 3P+E (3P+earthed) and has an earthing contact in a 6 h position (a 6 o'clock direction) is arranged. At this moment, a user has to replace the power receiving plug interface of the containers, that is, use the 6 h plug to replace the 3 h plug, thereby guaranteeing normal power supply of the containers. Great inconvenience is brought to users due to a problem of poor universality in an existing industrial plug.